public class Circle {
    public static final double Π = 3.14;

    private double r = 10;

    public double area() {
        return Π * r * r;
    }

    public static void main(String[] args) {
        Circle circle = new Circle();
        double area = circle.area();
        System.out.println("园的半径是" + area);
    }
}
